Liquid crystal display panel

ABSTRACT

A laminated spacer portion formed by laminating various thin films that constitute thin-film transistors is disposed in peripheral driver circuits. As a result, even in a structure in which part of a sealing member is disposed above the peripheral driver circuits, pressure exerted from spacers in the sealing member is concentrated on the laminated spacer portion, whereby destruction of a thin-film transistor of the peripheral driver circuits can be prevented caused by the pressure from the sealing portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits, as well as tovarious apparatuses using such a panel.

2. Description of the Related Art

An active matrix liquid crystal display panel is known in which anactive matrix circuit and peripheral driver circuits for driving it areintegrated on a glass substrate or a quartz substrate. In such an activematrix liquid crystal display panel, various measures have been taken tominimize the area of portions unnecessary for display, i.e., the areaoccupied by the peripheral driver circuits.

On the other hand, in the liquid crystal display panel, a sealing memberis provided in a peripheral portion to hold, i.e., confine a liquidcrystal between a pair of substrates. As one measure to minimize theareas of portions unnecessary for display, it is now required to reducethe area occupied by the sealing member.

The active matrix liquid crystal display panel which is integral withthe peripheral driver circuits has a problem that failures likely occurin the peripheral driver circuits. This tendency is more remarkable in aconfiguration in which part of the sealing member is disposed above theperipheral driver circuits.

This problem occurs in the following manner. The sealing member containsa kind of spacer called a filler to maintain the gap between thesubstrates. In general, the peripheral driver circuits have a very highdegree of integration. In these circumstances, pressure is exerted fromthe filler on thin-film transistors and a wiring of the peripheraldriver circuits which are located right under the filler (the pressureis estimated to be very strong locally), so that a line disconnection, acontact failure, and even a disconnection of a semiconductor layer arelikely to occur.

Although spherical substrate gap holding means called spacers are alsoused in the active matrix area, the occurrence of failures in the activematrix area due to the existence of the spacers is not so serious as inthe peripheral driver circuits, because the degree of integration is lowin the active matrix area.

SUMMARY OF THE INVENTION

An object of the present invention is to minimize the area of portionsother than a pixel matrix circuit in an active matrix liquid crystaldisplay panel which is integral with peripheral driver circuits.

Another object of the invention is to prevent destruction of aperipheral driver circuit due to pressure exerted from a sealing membereven in the active matrix liquid crystal display panel that attains theabove object.

According to a first aspect of the invention, as shown in FIGS. 1A to 1Dand 2 in the form of a specific manufacturing process, there is provideda liquid crystal display panel comprising an active matrix circuit(pixel circuit); a peripheral driver circuit, the active matrix circuitand the peripheral driver circuit being integrated on the same substrate101; a sealing member (indicated by numeral 206 in FIG. 2), part of thesealing member being disposed above the peripheral driver circuit;thin-film transistors formed in the peripheral driver circuit; and aprotrusion (laminated spacer) formed in the peripheral driver circuit,the protrusion being a lamination of materials that constitute thethin-film transistors, the protrusion being projected (see FIG. 1D) fromportions where the thin-film transistors are disposed.

According to a second aspect of the invention, as shown in FIGS. 1A to1D and 2 in the form of a specific manufacturing process, there isprovided a liquid crystal display panel comprising an active matrixcircuit (pixel circuit); a peripheral driver circuit, the active matrixcircuit and the peripheral driver circuit being integrated on the samesubstrate 101; a sealing member (indicated by numeral 206 in FIG. 2),part of the sealing member being disposed above the peripheral drivercircuit; thin-film transistors formed in the peripheral driver circuit;and a protrusion (laminated spacer) formed in the peripheral drivercircuit in addition to the thin-film transistors, the protrusion being alamination of materials that constitute the thin-film transistors, theprotrusion being higher (see FIG. 1D) than portions where the thin-filmtransistors are disposed.

According to a third aspect of the invention, as shown in FIGS. 1A to 1Dand 2 in the form of a specific manufacturing process, there is provideda liquid crystal display panel comprising an active matrix circuit(pixel circuit); a peripheral driver circuit, the active matrix circuitand the peripheral driver circuit being integrated on the same substrate101; a sealing member (indicated by numeral 206 in FIG. 2), part of thesealing member being disposed above the peripheral driver circuit;thin-film transistors formed in the peripheral driver circuit; and aprotrusion formed in the peripheral driver circuit in addition to thethin-film transistors, the protrusion being a lamination of materialsthat constitute the thin-film transistors, the protrusion having afunction of a spacer.

According to a fourth aspect of the invention, as shown in FIGS. 1A to1D and 2 in the form of a specific manufacturing process, there isprovided a liquid crystal display panel comprising an active matrixcircuit (pixel circuit); a peripheral driver circuit, the active matrixcircuit and the peripheral driver circuit being integrated on the samesubstrate 101; a sealing member (indicated by numeral 206 in FIG. 2),part of the sealing member being disposed above the peripheral drivercircuit; thin-film transistors formed in the peripheral driver circuit;and a laminated portion (laminated spacer) formed in the peripheraldriver circuit in addition to the thin-film transistors, the laminatedportion having more laminated layers (see FIG. 1D) than portions wherethe thin-film transistors are disposed in the peripheral driver circuit.

As shown in FIGS. 1A to 1D and 2, the protrusion (laminated spacer) isformed by laminating all the thin films that constitute the pixelcircuit and the peripheral driver circuits, the latter circuits having ahigh degree of integration. With this structure, pressure exerted fromspacers 204 in the sealing member 206 is concentrated on the protrusion.As a result, the thin-film transistors and the wiring of the peripheraldriver circuits can be prevented from being damaged.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1D are sectional views showing a manufacturing process of anactive matrix liquid crystal panel according to Embodiment 1 of thepresent invention;

FIG. 2 is a sectional view showing the active matrix liquid crystalpanel according to Embodiment 1 of the invention; and

FIGS. 3A to 3E show apparatuses to which a liquid crystal display panelof the invention is applied according to Embodiment 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[Embodiment 1]

This embodiment is directed to an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits. FIGS. 1A to 1Dand 2 show its manufacturing process.

This embodiment is directed to manufacture of a liquid crystal displaypanel that is constituted of a pixel circuit (active matrix circuit) andperipheral driver circuits for driving it. For example, the peripheraldriver circuits are composed of a shift register circuit, a buffercircuit, and a sampling circuit.

First, a base film (not shown) is formed on a glass substrate 101.Alternatively, a quartz substrate may be used. In this embodiment, a3,000-Å-thick silicon oxide film is formed by plasma CVD as the basefilm.

A 500-Å-thick amorphous silicon film (not shown) is then formed bylow-pressure thermal CVD.

A crystalline silicon film is obtained by crystallizing the amorphoussilicon film by illuminating it with laser light. Other means may beused to obtain a crystalline silicon film.

The thus-obtained crystalline silicon film is patterned into a pattern102, a pattern indicated by numerals 103 to 105, and a pattern indicatedby numerals 106 to 108. The pattern 102 will become a semiconductorpattern to constitute a laminated spacer 1000. The pattern indicated bynumerals 103 to 105 will become an active layer pattern of a thin-filmtransistor in a peripheral driver circuit 1001. The pattern indicated bynumerals 106 to 108 will become an active layer pattern of a thin-filmtransistor in a pixel circuit (active matrix circuit) 1002.

The laminated spacer is a laminated protrusion of all the componentsthat are formed intentionally in the TFT substrate. If the laminatedspacer is disposed in a peripheral driver circuit, pressure from thespacers for holding the substrate gap is concentrated on the laminatedspacer. As a result, pressure exerted on thin-film transistors and awiring that constitute the peripheral driver circuits can be reduced.

In this embodiment, it is assumed that all the illustrated thin-filmtransistors are of an n-channel type. In general, the peripheral drivercircuits are constituted of n-channel and p-channel thin-filmtransistors. On the other hand, n-channel or p-channel transistors areused in the pixel circuit.

After the patterning of the semiconductor layer, a gate insulating film109 is formed, and then an aluminum film (not shown) for forming gateelectrodes (and gate lines extending therefrom) is formed on the gateinsulating film 109. In this embodiment, a 4,000-Å-thick aluminum filmis formed by sputtering by using an aluminum target containing scandiumat 0.18 wt %.

The thus-formed aluminum film is patterned into aluminum patterns 110 to112. The pattern 110 is an aluminum pattern to constitute the laminatedspacer. The pattern 111 is a gate electrode of the thin-film transistorin the peripheral driver circuit. The pattern 112 is a gate electrode ofthe thin-film transistor in the pixel circuit.

Subsequently, 1,000-Å-thick anodic oxide films 113 to 115 are formed byanodization in which the aluminum patterns 110 to 112 are used as theanodes. Thus, the state of FIG. 1A is obtained.

Silicon nitride films may be used instead of anodic oxide films. As afurther alternative, oxide films (plasma oxide films) may be formed byplasma processing in an oxidizing atmosphere.

In the state of FIG. 1A, a 3,000-Å-thick silicon nitride film as a firstinterlayer insulating film 116 is formed by plasma CVD (see FIG. 1B).

After contact holes are formed, a multilayer metal film in which analuminum film is interposed between titanium films is formed bysputtering.

The three-layer metal film is patterned into a pattern 117, a sourceelectrode 118, a drain electrode 119, a source electrode 120, and adrain electrode 121. The pattern 117 will become part of the laminatedspacer. Thus, the state of FIG. 1B is obtained.

Thereafter, a 15,000-Å-thick resin layer 122, specifically a polyimidelayer, as a second interlayer insulating film is formed by spin coating.The use of the resin layer 122 is advantageous in that its surface canbe made flat

Subsequently, a 3,000-Å-thick titanium film is formed by sputtering, andthen patterned into a pattern 124 and a pattern 125. The pattern 124 isa titanium film pattern to become part of the laminated spacer. Thepattern 125 is a black matrix (BM), which has a function of shieldingthe thin-film transistors in the pixel circuit from light.

Then, a 3,000-Å-thick resin layer 126, specifically a polyimide layer,as a third interlayer insulating film 126 is formed by spin coating.

After contact holes are formed, a 1,000-Å-thick ITO film is formed overthe entire surface by sputtering. The ITO film is patterned into apattern 127 and an ITO pixel electrode 128. The pixel electrode 128 isin contact with the drain electrode 121. An auxiliary capacitance isformed in a region where the pixel electrode 128 and the black matrix125 coextend. Thus, the state of FIG. 1D is obtained.

The ITO pattern 127 is also left, as a dummy, in the laminated spacerportion. This makes the laminated spacer portion the thickest in theentire substrate structure. That is, the laminated spacer portion isprovided as a protrusion which is wider than a given area and in whichall the components are laminated.

Subsequently, an opposed glass substrate 201 (or a quartz substrate) isprepared as shown in FIG. 2. An opposed electrode 202 and an orientationfilm 203 are formed on the opposed glass substrate 201.

Reference numeral 206 denotes a sealing member, and numerals 204 and 205denote spacers included in the sealing member 206. A liquid crystal 207is sealed within the liquid crystal cell by the sealing member 206.

In the structure shown in FIG. 2, pressure exerted from the spacers 204and 205 is concentrated on the laminated spacer portion. This is becausethe laminated spacer portion is a highest protrusion having a certainarea.

The coextending portion of the black matrix 125 and the pixel electrode128 in the pixel circuit is equal in height (i.e., thickness) to thelaminated spacer portion. However, since the coextending portion hasonly a small area and the degree of integration is low in the pixelcircuit, the occurrence of wiring disconnections and TFT failures due topressure exerted from the spacer 208 is negligible.

The structure of FIG. 2 is particularly advantageous in that linedisconnections and operation failures of TFTs can be prevented in theperipheral driver circuit regions where the degree of integration ishigh.

As described above, by providing the laminated spacer in the activematrix liquid crystal display panel which is integral with theperipheral driver circuits, the peripheral driver circuits can beprevented from being damaged by pressure exerted from spacers that areincluded in the sealing member even if part of the sealing member isdisposed above the peripheral driver circuits.

[Embodiment 2]

This embodiment is directed to a case where the invention is applied toa configuration in which not only the peripheral driver circuits butalso various processing circuits and memory circuits are integrated onthe same substrate.

The structure called "system on panel" has been proposed as an advancedversion of the liquid crystal display panel which is integral with theperipheral driver circuits. In this new structure, various processingcircuits and memory circuits as well as the active matrix circuit andthe peripheral driver circuits are integrated on the same substrate.This structure is intended to reduce the size of an informationprocessing terminal by integrating its functions on a single glasssubstrate.

Also in this structure, it is required to reduce the area of theportions other than the pixel circuit (active matrix circuit). Thisnecessarily requires a structure in which the sealing member isoverlapped with various integrated circuits which constitute variousprocessing circuits and memory circuits.

To satisfy this requirement, the laminated spacer as described in thefirst embodiment may be provided in such integrated circuits, wherebythe integrated circuits constituting various processing circuits andmemory circuits which are high in the degree of integration can beprevented from being damaged by pressure exerted from spacers in thesealing member.

[Embodiment 3]

An active matrix liquid crystal display panel which is integral withperipheral driver circuits according to the invention can beincorporated in various apparatuses.

The use of the invention in an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits is veryadvantageous because in such a panel the peripheral driver circuits arerequired to have a high degree of integration.

FIG. 3A shows a digital still camera, an electronic camera, or animaging apparatus called "video movie" which can deal with motionpictures.

This apparatus has a function of electronically storing pictures takenby a CCD camera (or some other proper imaging means) that isincorporated in a camera section 2002. The apparatus also has a functionof displaying a picture thus taken on a liquid crystal display panel2003 that is incorporated in a main body 2001. The apparatus is operatedby using operation buttons 2004.

By applying the invention to this apparatus, the non-display area of theliquid crystal display panel 2003 can be minimized which enablesminiaturization of the apparatus.

FIG. 3B shows a portable personal computer (information processingapparatus). Provided with a liquid crystal display panel 2104 in a cover2102 that is attached to a main body 2101 and possible to open andclose, this apparatus allows a user to input various information orperform operations for various computations through a keyboard 2103.

FIG. 3C shows a case where a flat panel display is used in a carnavigation system (information processing apparatus). The car navigationsystem consists of an antenna section 2304 and main body 2301 thatincorporates a liquid crystal display panel 2302.

Switching among various pieces of information needed for navigation isperformed by operation buttons 2303. A remote controller (not shown) iscommonly used for various operations.

FIG. 3D shows an example of a projection image display apparatus. Asshown in FIG. 3D, light emitted from a light source 2402, formed in amain body 2401, optically modulated into an image by a liquid crystaldisplay panel 2403. The image is reflected projected onto a screen 2406after being reflected by mirrors 2404 and 2405.

FIG. 3E shows an example in which a main body 2501 of a video camera(imaging apparatus) is provided with a display device called a viewfinder.

The view finder is generally composed of a liquid crystal display panel2502 and an eyepiece unit 2503 which displays an image.

The video camera of FIG. 3E is operated by using operation buttons 2504,and pictures are recorded on a magnetic tape that is accommodated in atape holder 2505. Pictures taken by a camera (not shown) is displayed onthe liquid crystal display panel 2502. Pictures recorded on the magnetictape are displayed on the display panel 25O2.

In the video camera of FIG. 3E, it is required to minimize the area ofthe portions of the liquid crystal display panel 2502 other than thedisplay region (pixel region). Therefore, the employment of theconfiguration as described in the first embodiment is very advantageous.

As described above, the area of the portions other than the pixel matrixcircuit can be minimized in an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits.

It becomes possible to prevent destruction of a peripheral drivercircuit due to pressure exerted from the sealing member even in theactive matrix liquid crystal display panel in which the area of thenon-display portions is minimized.

What is claimed is:
 1. A liquid crystal display panel comprising:a pixelportion formed over a substrate, said pixel portion including at least aswitching element and a pixel electrode; a peripheral driver circuitformed over said substrate; a sealing member formed over said substrate,a part of said sealing member being formed over said peripheral drivercircuit; at least a thin-film transistor formed in the peripheral drivercircuit; and a protrusion formed in the peripheral driver circuit, saidprotrusion being a lamination of materials that constitute the thin-filmtransistor, wherein said protrusion is more projected than saidthin-film transistor in the peripheral driving circuit.
 2. A liquidcrystal panel according to claim 1, wherein said peripheral drivingcircuit includes at least one selected from the group consisting of ashift register circuit, a buffer circuit, and a sampling circuit.
 3. Aliquid crystal panel according to claim 1, wherein the thin filmtransistor is a top-gate type.
 4. The liquid crystal panel of claim 1,wherein said liquid crystal panel is used in one selected from the groupconsisting of a digital still camera, an electric camera, a video movie,a portable personal computer, a car navigation system, a projectionimage display apparatus, and a video camera.
 5. A liquid crystal displaypanel comprising:an active matrix circuit on a substrate; a peripheraldriver circuit on said substrate; a sealing member over said substrate,a part of said sealing member being formed above the peripheral drivercircuit; at least a thin-film transistor formed in the peripheral drivercircuit; and a protrusion formed in the peripheral driver circuit inaddition to the thin-film transistor, said protrusion being a laminationof materials that constitute the thin-film transistor, wherein saidprotrusion is higher than a portion where the thin-film transistor isformed.
 6. A liquid crystal panel according to claim 5, wherein saidperipheral driving circuit includes at least one selected from the groupconsisting of a shift register circuit, a buffer circuit, and a samplingcircuit.
 7. A liquid crystal panel according to claim 5, wherein thethin film transistor is a top-gate type.
 8. The liquid crystal panel ofclaim 5, wherein said liquid crystal panel is used in one selected fromthe group consisting of a digital still camera, an electric camera, avideo movie, a portable personal computer, a car navigation system, aprojection image display apparatus, and a video camera.
 9. A liquidcrystal display panel comprising:an active matrix circuit on asubstrate; a peripheral driver circuit on said substrate; a sealingmember over said substrate, a part of the sealing member being disposedabove the peripheral driver circuit; at least a thin-film transistorformed in the peripheral driver circuit; and a laminated portion formedin the peripheral driver circuit in addition to the thin-filmtransistor, said laminated portion having more laminated layers than aportion where the thin-film transistor is formed.
 10. A liquid crystalpanel according to claim 9, wherein said peripheral driving circuitincludes at least one selected from the group consisting of a shiftregister circuit, a buffer circuit, and a sampling circuit.
 11. A liquidcrystal panel according to claim 9, wherein the thin film transistor isa top-gate type.
 12. The liquid crystal panel of claim 9, wherein saidliquid crystal panel is used in one selected from the group consistingof a digital still camera, an electric camera, a video movie, a portablepersonal computer, a car navigation system, a projection image displayapparatus, and a video camera.
 13. A semiconductor device comprising:anactive matrix circuit region on a substrate, said active matrix circuitregion having at least a first thin film transistor, wherein said firstthin film transistor comprises,a first semiconductor island over saidsubstrate, said first semiconductor island having a first source anddrain regions and a first channel region, a first gate electrode formedover said first semiconductor island having a gate insulating filmtherebetween, first source and drain electrodes contacting said firstsource and drain regions through a first interlayer insulating film,said first interlayer insulating film covering said first thin filmtransistor, a first pattern over at least said first gate electrodehaving said first interlayer insulating film and a second interlayerinsulating film therebetween, a pixel electrode contacting said firstdrain electrode through a third interlayer insulating film; a peripheraldriver circuit region on said substrate, said peripheral driver circuitregion having a second thin film transistor and a laminated portion,wherein said second thin film transistor comprises,a secondsemiconductor island over said substrate, said second semiconductorisland having a second source and drain regions and a second channelregion, a second gate electrode formed over said second semiconductorisland having said gate insulating film therebetween, second source anddrain electrodes contacting said second source and drain regions throughsaid first interlayer insulating film, said first interlayer insulatingfilm covering said second thin film transistor, wherein said thirdinterlayer insulating film is formed on said second interlayerinsulating film formed on said second thin film transistor, and whereinsaid laminated portion comprises,a third semiconductor island over saidsubstrate, a second pattern over said third semiconductor island havingsaid gate insulating film therebetween, said second pattern being formedby a same material as said first gate electrode and said second gateelectrode, a third pattern over said second pattern having said firstinterlayer insulating film, said third pattern being formed by a samematerial as said first source and drain electrodes and said secondsource and drain electrodes; a fourth pattern over said third patternhaving said second interlayer insulating film therebetween, said fourthpattern being formed by a same material as said first pattern, a fifthpattern over said fourth pattern having said third interlayer insulatingfilm therebetween, said fifth pattern being formed by a same material assaid pixel electrode.
 14. A device according to claim 13, wherein saidperipheral driving circuit region includes at least one selected fromthe group consisting of a shift register circuit, a buffer circuit, anda sampling circuit.
 15. A device according to claim 13, wherein each ofthe first and second thin film transistors is a top-gate type.
 16. Adevice according to claim 13, wherein said semiconductor device is oneselected from the group consisting of a digital still camera, anelectric camera, a video movie, a portable personal computer, a carnavigation system, a projection image display apparatus, and a videocamera.
 17. A semiconductor device including at least a liquid crystaldisplay panel comprising:a pixel portion formed over a substrate, saidpixel portion including at least a switching element and a pixelelectrode; a peripheral driver circuit formed over said substrate; asealing member formed over said substrate, a part of said sealing memberbeing formed over the peripheral driver circuit; at least a thin filmtransistor formed in the peripheral driver circuit; and a protrusionformed in the peripheral driver circuit in addition to the thin filmtransistor, said protrusion including a lamination of materials thatconstitute the thin film transistor, wherein said protrusion is higherthan the thin film transistor.
 18. A device according to claim 17,wherein said peripheral driving circuit includes at least one selectedfrom the group consisting of a shift register circuit, a buffer circuit,and a sampling circuit.
 19. A device according to claim 17, wherein thethin film transistor is a top-gate type.
 20. A device according to claim17, wherein said semiconductor device is one selected from the groupconsisting of a digital still camera, an electric camera, a video movie,a portable personal computer, a car navigation system, a projectionimage display apparatus, and a video camera.
 21. A semiconductor deviceincluding at least a liquid crystal display panel comprising:a pixelportion formed over a substrate, said pixel portion including at least aswitching element and a pixel electrode; a peripheral driver circuitformed over said substrate; a sealing member over said substrate, a partof the sealing member being disposed over the peripheral driver circuit;at least a thin film transistor formed in the peripheral driver circuit;and a laminated portion formed in the peripheral driver circuit inaddition to the thin film transistor, said laminated portion having morelaminated layers than the thin film transistor.
 22. A device accordingto claim 21, wherein said peripheral driving circuit includes at leastone selected from the group consisting of a shift register circuit, abuffer circuit, and a sampling circuit.
 23. A device according to claim21, wherein the thin film transistor is a top-gate type.
 24. A deviceaccording to claim 21, wherein said semiconductor device is one selectedfrom the group consisting of a digital still camera, an electric camera,a video movie, a portable personal computer, a car navigation system, aprojection image display apparatus, and a video camera.